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They move almost as
rapidly as the little leaflets of Desmodium gyrans, alternately backwards
and forwards through from 20 to 40 degrees, in a plane at right angles to
that of the frond. The apex of the frond describes "a long and very narrow
ellipse," so that it circumnutates. But the movement differs from ordinary
[[page 258]]
circumnutation as it occurs only when the plant is exposed to the light;
even artificial light "is sufficient to excite motion for a few minutes."
[page 258]
In the chapter on the Sleep of Plants the conspicuous circumnutation of
Marsilea quadrifoliata (Marsileaceae, Fam. 4) will be described.
It has also been shown in Chap. I. that a very young Selaginella
(Lycopodiaceae, Fam. 6), only .4 inch in height, plainly circumnutated; we
may therefore conclude that older plants, whilst growing, would do the
same.
Fig. 120. Lunularia vulgaris: circumnutation of a frond, traced from 9 A.M.
Oct 25th to 8 A.M. 27th.
(35.) Lunularia vulgaris (Hepaticae, Fam. 11, Muscales).--The earth in an
old flower-pot was coated with this plant, bearing gemmae.


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